Users who do not have the required permission will be able to see unauthorized items , by using the Export To Excel button

I have created the following custom security permission, which should allow users to ONLY create new items , without being able to view, edit, delete any items . and it worked well from the first test.

$spweb=Get-SPWeb -Identity "Site URL";

$spRoleDefinition = New-Object Microsoft.SharePoint.SPRoleDefinition;
$spRoleDefinition.Name = "Submit only";
$spRoleDefinition.Description = "Can submit/add forms/files/items into library or list but cannot view/edit them.";
$spRoleDefinition.BasePermissions = "AddListItems, ViewPages, ViewFormPages, Open";
$spweb.RoleDefinitions.Add($spRoleDefinition);
$spweb.Dispose();
But now I login with a user, who is assigned to the custom security level, and I went to a list view, and he could not see any result as follow:-

So I though that the custom security level worked well, but if the user simply go to >>List Options>> and he click on “Export to Excel” he will see the following inside the excel client :-

and when he click on Enable , then he can see all the items inside the excel sheet, although these items are not visible inside the list view as follow:-

Can anyone advice on this critical issue please? Thanks